The objective of this research program is the investigation of evoked potential correlates of the perception of linguistic meaning in speech and reading with goal of better understanding of the neural mechanisms of language processing. Specifically, we will study EP waveform differences produced by different contextual meanings of the same stimulus work, try to identify the critical linguistic parameters associated with EP differences and the cortical distribution of EP differences. In the couse of these investigations we hope to determine which EP parameters are constant across subjects, and which are idiosyncratic. Long-range goals include the investigation of language development and dysfunction using this methodology. The primary methodology involves the study of human average cortical potentials evoked by words (homonyms) presented visually and acoustically, which have up to four different meanings, with the specific meaning dependent upon the context in which the word is presented. Meaning-produced EP waveform differences will be evaluated in terms of scale areas from which responses are recorded, and linguistic parameters involved in the meaning of the stimulus word. EP differences will be assessed using the methods of correlation, stepwise discriminant analysis, and component analysis.